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# Myelodysplastic syndromes

Bone marrow cancers in which blood cells form but grow abnormally, causing low blood counts; some cases turn into acute myeloid leukaemia.

Updated 2026-11-01

## Structures involved

Tap one to see what it is and open it in 3D.

- [Sternum](https://durgical.com/en/anatomy/sternum/)
- [Hip bone](https://durgical.com/en/anatomy/hip-bone/)
- [Ribs (back part)](https://durgical.com/en/anatomy/ribs/)
- [Sacroiliac ligaments](https://durgical.com/en/anatomy/sacroiliac-ligaments/)

## Why it happens

- [Translocations, amplifications and epigenetic changes in cancer](https://durgical.com/en/general-pathology/translocations-amplifications-and-epigenetic-changes-in-cancer/)
- [Apoptosis: the intrinsic and extrinsic pathways](https://durgical.com/en/general-pathology/apoptosis-the-intrinsic-and-extrinsic-pathways/)
- [Ionizing radiation injury](https://durgical.com/en/general-pathology/ionizing-radiation-injury/)
- [Chemical carcinogens: initiation, promotion and the table to know](https://durgical.com/en/general-pathology/chemical-carcinogens-initiation-promotion-and-the-table-to-know/)
- [Hematopoiesis](https://durgical.com/en/physiology/hematopoiesis/)
- [Hematopoiesis and bone marrow](https://durgical.com/en/histology/hematopoiesis-and-bone-marrow/)

## What it is

A group of clonal disorders of the bone marrow stem cell in which blood cells are produced ineffectively and look abnormal (dysplastic). The result is low counts of red cells, white cells and/or platelets despite a marrow that is usually full of cells. They are considered cancers of the blood and carry a variable risk of progressing to acute myeloid leukaemia (AML).

## Who gets it

Mainly a disease of older adults, with a median age at diagnosis around 70 years and a slight male predominance; it is rare in children. Incidence rises steeply with age, so it is becoming more frequent as populations age in Colombia and Latin America. Therapy-related cases occur years after chemotherapy or radiotherapy for another cancer.

## Causes

- Primary (de novo): acquired mutations in marrow stem cells with ageing, usually without a known cause
- Therapy-related: previous alkylating agents, topoisomerase II inhibitors or radiotherapy
- Exposure to benzene, tobacco smoke and some pesticides or solvents
- Inherited marrow failure syndromes in younger patients (e.g. Fanconi anaemia)

## Risk factors

- Age over 60
- Previous chemotherapy or radiotherapy
- Smoking
- Occupational benzene or chemical exposure
- Aplastic anaemia or inherited bone marrow failure

## Pathophysiology

Acquired genetic changes (chromosome losses such as del(5q), monosomy 7, and mutations in splicing and epigenetic genes) give a stem cell clone a growth advantage. The clone fills the marrow, but its progeny mature abnormally and many die inside the marrow by apoptosis (ineffective haematopoiesis), so the blood shows cytopenias. Further mutations block maturation, blasts accumulate, and when they reach 20% of marrow cells the disease is classified as AML.

## Classification

- WHO classification, based on number of dysplastic lineages, ring sideroblasts, blast percentage and genetics (e.g. MDS with isolated del(5q), MDS with excess blasts); it replaced the older FAB system
- Risk scoring with IPSS or revised IPSS (IPSS-R), using marrow blasts, cytogenetics and the depth of cytopenias, separates lower-risk from higher-risk disease
- Therapy-related myeloid neoplasms are grouped separately; chronic myelomonocytic leukaemia is an overlap myelodysplastic/myeloproliferative neoplasm

## Symptoms and signs

- Fatigue, weakness, pallor and breathlessness (anaemia)
- Recurrent or severe infections (neutropenia)
- Easy bruising, petechiae, gum or nose bleeding (thrombocytopenia)
- Often no symptoms: found on a routine blood count
- [Spleen](https://durgical.com/en/anatomy/spleen/) and lymph nodes are usually not enlarged

## Red flags

- Fever in a patient with low neutrophils
- Active bleeding or very low platelets
- Rising blasts in blood or marrow (transformation to AML)
- Symptomatic anaemia with [chest](https://durgical.com/en/anatomy/region/chest/) pain or heart failure

## Diagnosis

**Clinical**
Consider it in an older adult with unexplained macrocytic anaemia or other persistent cytopenias. Ask about previous chemotherapy, radiotherapy and chemical exposure, and rule out reversible causes first.

**Tests**
Complete blood count with reticulocytes (often macrocytic anaemia with low reticulocytes) and peripheral smear (hypogranular, hypolobated neutrophils, oval macrocytes). Exclude vitamin B12, folate and copper deficiency, alcohol, drugs, HIV and [liver](https://durgical.com/en/anatomy/liver/) disease. The key test is bone marrow aspiration and biopsy, usually from the posterior iliac crest: dysplasia in at least 10% of a lineage, blast count, ring sideroblasts on iron stain, cytogenetics, FISH and gene mutation panels, plus flow cytometry.

**Imaging**
Not needed for diagnosis; imaging is used only to look for infections or other causes of cytopenia.

## Differential diagnosis

- Vitamin B12 or folate deficiency (megaloblastic anaemia)
- Aplastic anaemia (empty marrow)
- Acute myeloid leukaemia (20% or more blasts)
- Anaemia of chronic disease, alcohol, drugs, HIV or copper deficiency
- Myeloproliferative neoplasms and hereditary sideroblastic anaemia

## Goal of treatment

In lower-risk disease, improve blood counts and quality of life with few transfusions; in higher-risk disease, delay progression to AML and prolong survival, aiming for cure with transplantation where possible.

## Treatment

**Conservative**
Red-cell and platelet transfusions as needed; iron chelation for patients who become iron-overloaded after many transfusions; prompt antibiotics for infections.

**Medical**
Lower-risk disease: erythropoiesis-stimulating agents for anaemia; lenalidomide for transfusion-dependent MDS with isolated del(5q); immunosuppressive therapy in selected patients.

**Medical**
Higher-risk disease: hypomethylating agents (azacitidine, decitabine) are the main disease-modifying treatment; intensive AML-type chemotherapy in selected fit patients.

**Procedure**
Allogeneic haematopoietic stem cell transplantation is the only potentially curative treatment, limited to fitter patients because of its toxicity.

**Follow-up**
Nursing priorities: neutropenic and bleeding precautions, transfusion safety checks and reaction monitoring, early reporting of fever, and monitoring of ferritin and organ function in chronically transfused patients.

## Complications

- Severe infections and sepsis
- Bleeding, including intracranial haemorrhage
- Transformation to acute myeloid leukaemia
- Transfusional iron overload damaging heart, liver and endocrine glands
- Transfusion reactions and alloimmunisation

## Prognosis

Very variable and predicted by IPSS-R category: lower-risk patients may live many years with supportive care, while higher-risk patients often survive only one to two years without transplantation, mostly dying from infection, bleeding or AML. Patients who stop responding to hypomethylating agents have a poor outlook.

## Prevention

- Avoid tobacco and protect workers from benzene and other solvents
- Long-term blood count follow-up after chemotherapy or radiotherapy

## Test yourself

Think of the answer, then tap the question to see it.

## What is the typical blood picture in myelodysplastic syndromes?

Cytopenias, often a macrocytic anaemia with low reticulocytes, despite a usually hypercellular marrow.

## Which test confirms myelodysplastic syndrome?

Bone marrow aspiration and biopsy with cytogenetics, showing dysplasia and the blast percentage.

## What blast percentage in the marrow defines progression to acute myeloid leukaemia?

20% or more blasts.

## Which MDS subtype responds especially well to lenalidomide?

Lower-risk MDS with isolated deletion of chromosome 5q.

## What is the only potentially curative treatment for MDS?

Allogeneic haematopoietic stem cell transplantation.

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## Related conditions

- [Acute leukaemia (AML and ALL)](https://durgical.com/en/conditions/acute-leukaemia/)
- [Aplastic anaemia](https://durgical.com/en/conditions/aplastic-anaemia/)
- [Megaloblastic anaemia (B12 or folate deficiency)](https://durgical.com/en/conditions/megaloblastic-anaemia/)
- [Sideroblastic anaemia](https://durgical.com/en/conditions/sideroblastic-anaemia/)
- [Anaemia of chronic disease (anaemia of inflammation)](https://durgical.com/en/conditions/anaemia-of-chronic-disease/)
- [Febrile neutropenia](https://durgical.com/en/conditions/febrile-neutropenia/)
- [Immune thrombocytopenia (ITP)](https://durgical.com/en/conditions/immune-thrombocytopenia/)
- [Transfusion reactions](https://durgical.com/en/conditions/transfusion-reactions/)
- [Hereditary hemochromatosis](https://durgical.com/en/conditions/hereditary-hemochromatosis/)
- [Essential thrombocythaemia and primary myelofibrosis](https://durgical.com/en/conditions/essential-thrombocythaemia-and-primary-myelofibrosis/)
- [Chronic myeloid leukaemia](https://durgical.com/en/conditions/chronic-myeloid-leukaemia/)

Educational information, not medical advice. For any symptom, see a health professional.

Sources: [Myelodysplastic Syndromes Treatment (PDQ®)–Health Professional Version](https://www.cancer.gov/types/myeloproliferative/hp/myelodysplastic-treatment-pdq) (National Cancer Institute, 2024); [Myelodysplastic Syndromes Treatment (PDQ®)–Patient Version](https://www.cancer.gov/types/myeloproliferative/patient/myelodysplastic-treatment-pdq) (National Cancer Institute, 2024).

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Source: https://durgical.com/en/conditions/myelodysplastic-syndromes/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/conditions/myelodysplastic-syndromes/